Railway cars are often used to transport bulk commodities and materials. In transporting such lading, it is desirable to provide railway cars that are efficient with respect to cost and ease of manufacture, load carrying capacity and energy required to move the cars throughout a railway system. Also, railway cars must be designed to meet various government regulatory standards and industry operating standards. For example, the Association of America Railroads (AAR) has established standardized operating envelopes which define maximum allowed exterior dimensions for a wide variety of railway cars. Many advances have been made with respect to making railway cars stronger, lighter, larger in volume, greater load carrying capacity, easier to manufacture, and more aerodynamic. However, the search continues for improved railway cars that are even more efficient and cost effective.
Hopper cars and gondola cars may be used to transport a wide variety of goods and materials such as bulk commodities (corn, wheat, soy beans, etc.) and raw materials (coal, iron ore and other minerals). Gondola cars typically have a pair of sidewalls, a pair of end walls, a solid floor, and no roof. Hopper cars may be either open or covered depending upon the type of bulk lading which will be carried within the respective hopper car. A typical hopper car includes floor sheets which are sloped from the sides and ends of the car to form a series of pockets or hoppers with openings which allow discharge of the bulk lading.
In designing a railway car, it is desirable to maximize volume available for loading, while at the same time, maintaining exterior dimensions of the railway car within the appropriate AAR operating envelope.
Increasing volume may be achieved by minimizing the thickness of the associated sidewalls as long as the sidewalls maintain sufficient strength and durability for the associated loading. Side posts or side stakes are often provided to stiffen sidewalls to help carry lateral loads and beam loads.
Frequently, railway cars, such as hopper cars and gondola cars, have numerous side posts spaced along each side of the respective car to provide such support. Some conventional hopper cars may have eleven (11) or more side posts extending along each side of the respective car. Numerous side posts increase material cost and complexity of the design and manufacture of the associated railway car. Frequently, side posts are placed on the exterior of the associated sidewall to increase interior volume or cargo carrying capacity of the resulting railway car. However, exterior side posts, which often have a rectangular cross section, may increase aerodynamic drag and reduce railway car operating efficiency. Also, relatively thick exterior side posts limit potential increases in cargo volume as compared to a similar railway car with interior side posts.